1. Field of the Invention
The present invention relates to a crawler crane capable of performing versatile operations.
2. Description of the Related Art
FIGS. 9 and 10 are a top view and a side view, respectively, of a conventional crawler crane 51. In this crane 51, a rigid revolving frame 54 is mounted to be traveled freely on a traveling rest provided with traveling crawlers 52 on both sides. A boom 55 for operation is mounted to be rocked back and forth on the extreme end of the revolving frame 54, and at the rear of the boom 55, a revolving device 56, a main (first) winding drum 57, an auxiliary (second) winding drum 58, and a third (third) drum 59 are arranged in a row to wind operating ropes. At the rear of the third drum 59 is arranged an engine 60 which drives a power plant comprising a hydraulic pump and the like not shown to supply pressure oil to the respective drums and also supply the driving force for revolution and traveling.
At the rear of the engine 60 is mounted a fall-down preventive counter-weight 61, front surface of which is flat so as not to interfere with the engine 60. On the other hand, on the frame projected on the left side forwardly of the revolving frame 54 is arranged a boom rising and falling drum 62 so as to wind a rope for rising and falling the boom 55. On the other hand, a cabin 63 is provided on the frame projected on the right side.
As shown in FIGS. 11A and 11B, each of the drums is braked by a dry brake 64 mounted on the side of the drum.
The crane 51 has various uses for operation, for example, such as a standard crane, a hammer-grab, a multiple wall bucket (hydraulic), a multiple wall bucket (mechanical), an earth drill, a clamshell, a logging, an earth auger, a down-the-hole, etc. In these operations, the vertical movement of a suspended load and a bucket is carried out by winding up and-down operation of the main winding drum 57 and the auxiliary winding drum 58 as standard equipment. On the other hand, casing jack handling in the hammer grab operation, vibro-at hand drawing in the vibro operation, crane operation in the operation on the vessel, and the like are carried out by the third drum 59 as optional equipment. The main winding drum 57 is used for opening and closing a clamshell bucket, the auxiliary winding drum 58 is used for supporting a clamshell bucket, and the third drum 59 is used for the installation crane operation such as tetra.
Generally, the crawler crane has restrictions in terms of body layout which is satisfied with the small rear end revolving radius required on the spot and which is necessary to mount a wide drum of large rope winding capacity. However, in the conventional crawler crane 51, when the third drum 59 is provided an optional equipment, only the third drum 59 which is smaller than the main winding drum 57 and the auxiliary winding drum 58 can be incorporated in terms of body layout as described above. Therefore, the diameter of a rope is so small in terms of restrictions of charge of a rope for the third drum 59 that multi-applying need be done when in raising, and the raising ability is restricted also. Accordingly, when the drum is used while adjusting to the use of operation, the third drum 59 exerts a considerable restriction on the use of operation.
Further, as shown in FIGS. 12 and 13, there is proposed a configuration 51xe2x80x2 wherein the engine 60 is arranged on the side of the revolving frame 54. Large dry brakes 64xe2x80x2 are provided doubly, as shown in FIGS. 14A and 14B, in order to secure the large braking force required for excavation operation or the like, and only the small third drum 59 can be incorporated. Note that other constitutions in FIGS. 12 to 14B are similar to those of the above-mentioned crawler crane 51, which are indicated by the same reference numerals.
It is an object of the present invention to provide a crawler crane capable of performing versatile operations.
The crawler crane according to the present invention comprises a revolving frame; a main winding drum, an auxiliary winding drum and a third drum mounted on said revolving frame to wind an operating rope, said drums being arranged in a row so that rotational shafts thereof are at right angles to a center shaft of a boom and mounted on said revolving frame; an engine including a power plant for supplying driving pressure oil to said main winding drum, said auxiliary winding drum and said third drum (said engine being mounted on either left or right side of said revolving frame); a counter-weight having a recess portion, front side of which is formed to have a recessed surface (said counter-weight being mounted at the rear of said main winding drum, said auxiliary winding drum and said third drum); and a boom accessory device installed within said recess portion.
In this case, the third drum of the size which is the same as or larger than said main winding drum and said auxiliary winding drum can be mounted on said revolving frame irrespective of the brake type of each of the drums. Therefore, the third drum is also able to obtain the raising ability which is the same as or greater than the main winding drum and the auxiliary winding drum. Drums can be selected for versatile operations by users.
In the conventional apparatus, the raising operation by the third drum has been carried out by multi-applying. In the present invention, however, the charge of the rope for the third drum increases, and the diameter of a rope for the third drum can be increased to reduce the number of applications for operation, thus enhancing the operating speed, and facilitating the charging operation for the rope. Further, since the third drum also can provide free falling similar to the main winding drum and the auxiliary winding drum.
Furthermore, the crawler crane according to the present invention comprises a revolving frame; a main winding drum, an auxiliary winding drum and a third drum mounted on said revolving frame to wind an operating rope, said drums being arranged in a row so that rotational shafts thereof are at right angles to a center shaft of a boom and mounted on said revolving frame; an engine including a power plant for supplying driving pressure oil to said main winding drum, said auxiliary winding drum and said third drum; and an encased type brake disposed on each drum to brake said main winding drum, said auxiliary drum and said third drum, respectively.
Since in this case, the third drum of the size which is the same as or larger than said main winding drum a said auxiliary drum can be mounted on said revolving frame irrespective of the shape of the counterweight, the third drum is also able to obtain the raising ability which is the same as or greater than the main winding drum and the auxiliary drum. Drums can be selected for versatile operations by users.
Moreover, if the constitutions of the above-mentioned crawler cranes are combined and applied, the geometrical operation and effect can be obtained advantageously.